Field of the Invention
The invention lies in the printing technology field. More specifically, the invention relates to a device for adjusting at least one register element in a printing machine, having an upper clamping rail, to which the register elements are fixed, and a clamping element which co-operates with the upper clamping rail. The invention further pertains to a corresponding method.
In addition, the invention relates to a method of adjusting at least one register element in a printing machine.
Devices and methods which can be implemented therewith of the type addressed here are known from European patent EP 0 596 337 B1. There, the clamping rail, in particular of a sheet-fed offset printing machine, is used to fix a printing plate to an associated plate cylinder. Because of tolerances which become established and are not desired in the printing machine and therefore also on the plate cylinder, it is necessary to provide a positional adjustment of the register elements (register pins) in relation to a fixed printing-plate leading edge. European patent EP 0 596 337 B1 discloses the practice of adjusting the position of the register elements in each case in relation to the clamping rail by means of an appropriately designed fixing mechanism. In this way, unavoidable inaccuracies or play on the plate cylinder of the printing machine, between the clamping rail and the printing plate to be fixed, are compensated for, so that a printing plate to be clamped can be fixed to the plate cylinder in a precise and correct manner by means of the register elements operatively connected to the clamping rail.
It is additionally known, in order to adjust the position of register elements, to adjust the position of the entire clamping railxe2x80x94comprising an upper clamping rail and a lower clamping strip co-operating with the latterxe2x80x94released from the plate cylinder together with the register elements. Since the clamping rail is operatively connected to the plate cylinder by means of a relatively large number of clamping means (clamping screws), loosening these clamping means for the subsequent positional adjustment of the clamping rail with register elements is disadvantageously time-consuming and complicated.
It is accordingly an object of the invention to provide a device adjusting at least one register element in a printing machine and a corresponding method, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which permits precise and rapid positional adjustment of the register elements, without having to loosen the operative connection between the register elements and the upper clamping rail for this purpose.
With the foregoing and other objects in view there is provided, in accordance with the invention, a device for adjusting a register element in a printing machine. The device comprises:
an upper clamping rail and a register element fixed to the upper clamping rail, wherein the upper clamping rail is movably disposed in a guide and fixable in position for adjusting the register element; and
a clamping element co-operating with the upper clamping rail.
In other words, the above objects are achieved with a device the other clamping rail of which can be moved in a guide and fixed in position in order to adjust the register element. In this case, the guide is preferably designed in such a way that, in every possible operating position of the clamping rail, it can compensate for the blocking forces which are established in order to fix a printing plate to the plate cylinder. The adjustment of the respective register element is therefore carried out by means of a suitable relative movement of the upper clamping rail relative to the plate cylinder, the corresponding register element being fixed in a stable position even during the adjustment operation on the upper clamping rail. By means of an upper clamping rail which is always guided during the adjustment operation, it is possible, by using an adjusting means which is suitably designed and operatively connected to the upper clamping rail, to achieve rapid and defined adjustment of the register element. At the same time, it is not necessary to detach the upper clamping rail completely from the plate cylinder in order to adjust the register element, instead, because of the guidance provided for the clamping rail, there is also the possibility to deform or to bend the latter elastically in an adjustment direction by means of a suitable adjusting means in order to achieve a positioning of the respective register element, which is established appropriately, relative to the printing plate to be fixed or to be clamped to the plate cylinder. After assuming a desired operating position of the elastically deformed clamping rail or of the associated register element, the clamping rail can be fixed in position on the plate cylinder by means of suitable clamping or tensioning means. In accordance with an added feature of the invention, the guide is advantageously a sliding guide, and the position of the upper clamping rail can be adjusted by means of an adjusting device in a sliding direction corresponding to the adjustment direction of the register element. A sliding guide can be implemented relatively simply in production terms and is particularly suitable to compensate for forces which are established in order to fix a printing plate to the plate cylinder and are radial in relation to the plate cylinder, precise guidance of the upper clamping rail on the plate cylinder being ensured at the same time. This makes it possible, by means of a defined positional adjustment of the clamping rail, while actuating a suitably designed adjusting device, to obtain rapid and correct adjustment of the respective register element.
According to a preferred embodiment, the adjusting device has at least one mechanical adjusting element for producing an adjusting force acting on the upper clamping rail. In this case, the mechanical adjusting element provided can be a setting screw suitably operatively connected to the upper clamping rail, a wedge, an eccentric pin or the like, by means of which adjustment of the upper clamping rail in tangential direction with regard to the plate cylinder can be achieved. A mechanical adjusting element of this type is preferably operated manually.
According to a further alternative embodiment, the adjusting device has at least one electrical adjusting element for producing an adjusting force acting on the clamping rail. In this case, for example, the use of bundled piezoelectric actuators can be provided, by means of which an electrically triggerable introduction of force into the upper clamping rail in order to adjust the position of the same can be implemented. In this case, electrically operated adjusting elements are particularly suitable for the automated adjustment of the respective register element by means of a suitable, preferably central, control unit.
Clamping or tensioning means are advantageously provided to fix the position of the clamping rail. Clamping or tensioning means of this type, serving to lock or fix the deformed clamping rail, or the clamping rail displaced without elastic bending, can be designed as clamping screws, for example. In addition, it is possible to implement the positional fixing of the clamping rail by means of electrically operated clamping or tensioning means, so that automated fixing of the position of the clamping rail by means of a preferably central control unit is also possible.
The device is advantageously operatively connected to a central control unit. By means of a central control unit, by using electrically operated adjusting elements and positional fixing means for the clamping rail, automated and controlled adjustment of the respective register element can be carried out.
According to a further, alternative embodiment, the clamping rail comprises a multiplicity of relatively mobile part segments, each of which contains at least one register element. This makes it possible to adjust the positions of relatively guided part segments of the upper clamping rail independently of one another, preferably counter to an elastic restoring force, for example resulting from elastic bending of the corresponding part segment. Particularly flexible and preferably automated adjustment of the respective register element can therefore be implemented by means of a controlled movement of the corresponding part segment.
With the above and other objects in view there is also provided, in accordance with the invention, a method of adjusting at least one register element in a printing machine, which comprises providing an upper clamping rail having fixed thereto the register element, and moving the upper clamping rail in a guide and fixing the clamping rail in position in order to adjust the register element.
In other words, the objects are achieved with a method of adjusting at least one register element in a printing machine in which an upper clamping rail, to which the register element is fixed, is moved in a guide and fixed in position in order to adjust said register element. This method according to the invention is suitable to achieve the advantages previously mentioned with reference to the device.
The position of the clamping rail is preferably adjusted in a sliding guide by means of an adjusting device in the adjustment direction of the register element. The position of an upper clamping rail guided in a sliding guide can be adjusted precisely in a particularly reliable manner and is therefore suitable for finely set register element adjustment.
According to a preferred design variant, the adjusting force acting on the clamping rail is produced mechanically. This can be carried out, for example, by means of a manual adjustment of appropriately designed adjusting elements.
According to a further alternative design variant, the adjusting force acting on the upper clamping rail is produced electrically. The adjusting elements used for this purpose can be controlled, in a relatively simple way, by means of a central control unit, so that the adjustment of a respective register element can advantageously be automated.
The upper clamping rail is preferably fixed in position at a point and, at adjustment regions, wherein the register element is arranged and is guided in the adjustment direction, is deformed elastically and firmly clamped in a stable position. In this case, it is not necessary to loosen the point positional fixing of the upper clamping rail to the plate cylinder of the printing machine by means of elastic deformation in one or more adjustment regions in order to achieve a defined positional adjustment of the upper clamping rail, so that rapid and precise adjustment of the register element can be implemented.
Moving and fixing the position of the upper clamping rail in the guide is preferably carried out in an automated manner, and in particular by means of a central control unit. In this case, any play which may be present between the upper clamping rail and a printing plate to be clamped firmly to the plate cylinder can be determined by means of suitably arranged measuring means (sensors) and transmitted to the central control unit, which initiates a corresponding, automated adjustment of the position of the upper clamping rail and therefore suitable positioning of the respective register element by means of electrically controllable adjusting elements.
Corresponding to an alternative design variant, the upper clamping rail comprises a multiplicity of part segments which have at least one register element and are moved and fixed in position independently of one another. In this way, particularly flexible adjustment of the register elements by means of preferably elastic and automated deformation of the part segments is made possible, the part segments and therefore also the corresponding register elements being adjustable independently of one another.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a device for adjusting at least one register element in a printing machine, and corresponding method, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.